Water safety and purity is a civic necessity of utmost importance. Human health and safety dictates that drinking and other home use water must meet various health and environmental standards. Contaminated equipment or fluids at various sources in the water supply can affect thousands of homes and lives. Sabotage and attacks on the water supply must not only be prevented, but rapidly detected. Consumers feel increasingly insecure about the water in their home taps. Despite water purification by state and local municipalities, many consumers install filtration systems in order to purify their water.
Public water utilities and state and local agencies typically perform contaminant detection at water treatment centers, public water supplies and wells, and other central locations in the water distribution system by grab sampling, which means that technicians collect field samples or perform measurements in the field. A common analytic technique for measuring water quality is to determine the level of Total Organic Carbon (“TOC”) in the water. TOC can come from decaying organic matter or synthetic sources such as industrial chemicals or fertilizers, and as such is an indicator of water quality.
Typical TOC analyzers are large and expensive devices that are best suited for utilization on-site at central locations in the water supply. Some devices burn the sample in a furnace then analyze remaining CO2, which is directly proportional to the amount of carbon in the sample. More recently, UV254 has been used as a TOC substitute, wherein the amount of UV254 absorbed by the water is known to be proportional to the concentration of organic carbon matter in the water. Devices that use UV254 typically use a large light source with large power requirement, for high accuracy measurement. Furthermore, these instruments use a standing sample of water, to further increase their accuracy.
Other water contaminants that consumers seek to detect and filter include heavy metals, Total Dissolved Solids (TDS), turbidity, and other bacteria. Many types of filters are commercially available to trap and remove pollutants such as organic and man-made chemicals, heavy metals, sediments, radioactive isotopes, etc. Such filters come in many forms, including activated carbon, carbon block, reverse osmosis, and ion exchange filters. Typical commercially available consumer filters are contained within water pitchers, installable onto faucets and taps, and some are incorporated into the building's plumbing.